A vehicle, like an automobile, may be susceptible to a rollover. A rollover is a type of vehicle accident in which a vehicle tips over onto its side or roof. All vehicles are susceptible to rollovers to various extents. Generally, the higher the center of mass, the more sensitive the steering, and the higher the speed, the more likely it is to roll over. The most common cause of a rollover is traveling too fast while turning. However, vehicles can roll over in several ways including, but not limited to, excessive cornering speed, tripping, or traversing a critical slope. The instant invention is designed to provide a rollover warning system designed to help reduce rollovers due to excessive cornering speed, tripping and/or traversing a critical slope by indicating to a driver when a vehicle is at risk of rolling over.
Rollovers caused by excessive cornering speed occur when cornering forces destabilize the vehicle. As a vehicle rounds a corner, three forces act on it: tire forces, inertial effects, and gravity. The cornering forces from the tire push the vehicle towards the center of the curve. This force acts at ground level. The force of inertia acts horizontally through the vehicle's center of mass in the direction opposite to the one it is turning. These two forces make the vehicle roll towards the outside of the curve. The force of the vehicle's weight acts downward through the center of mass in the opposite direction. When the tire and inertial forces are enough to overcome the force of gravity, the vehicle starts to turn over. This is a common type of rollover for taller vehicles, including light trucks (SUVs, vans and pickup trucks), buses, heavy trucks, and military vehicles.
A rollover can also occur as a vehicle crosses a ditch or slope. Steep slopes are called ‘critical slopes’ (typically refers to slopes over 33%) and often contribute to rollovers. A vehicle may rollover for other reasons, such as when hitting a large obstacle with one of its wheels or when maneuvering over uneven terrain.
Automobiles, like cars, off-road vehicles, trucks, tractor-trailors, and most any vehicle can be susceptible to a rollover. However, the invention is not just limited to automobiles. Other vehicles are also known to be highly susceptible to rollovers. For example, agricultural equipment like tractors, mowers etc., construction equipment including skid steer loaders (e.g. Bobcats), bulldozers, etc., ATVs, and other vehicle types are also known to rollover. Thus, there is clearly a need to provide a rollover warning system that is adapted to be added to any vehicle to help a driver prevent a rollover and reduce the risk of injury and damage to the vehicle and/or equipment. In addition, some military vehicles are known to be highly susceptible to rollovers. Military vehicles have a much wider wheel track than civilian SUVs, making them more difficult to roll over. However, improvised explosive devices (IEDs) and poor road construction in military environments (like Iraq and Afghanistan) cause rollovers not seen by civilian vehicles. For example, many military vehicles include “V” shaped hulls which give the vehicles a higher center of gravity.
Another cause of a rollover can be due to operator error, or by an “incidental driver” or “incidental operator”, i.e. an operator who may not be trained on a particular vehicle. An untrained driver or operator may get into a High-CG vehicle (like an MRAP) after getting out of his/her personal car or their HMMWV (which has a lower CG) and then turn the MRAP over because they were not acclimated to the vehicle. Thus, there is a need for a system to warn such an untrained driver, incidental driver or incidental operator of the rollover risk of the vehicle they are operating in.
There are commonly two types of rollover warning systems commonly available today. The first type of rollover warning system is a simple sensor which measures the angle of the vehicle, typically with a single accelerometer. The problem with this type of simple sensor is that it is not accurate when other forces are acting on the sensors, like centrifugal forces from cornering. Thus, there is clearly a need for a more accurate rollover warning system. The second type of rollover warning system is a much more complex system that is linked to the computer system of the vehicle. This second type of system takes parameters like the vehicles speed, steering wheel angle, etc. to determine the likelihood of the vehicle rolling over. The problem with this type of system is that it is not readily retrofitted onto an existing vehicle or fitted to less complex vehicles, or fitted to vehicles independent of using their complex electronic sensors. In addition, the system is very complex and thus can be very expensive. Thus, there is clearly a need for a rollover warning system that is capable of being retrofitted into an existing vehicle (i.e. it does not need to be linked to the vehicle's computer system) and is capable of producing accurate results and by design reduces or eliminates false alarms caused by methods which use only an accelerometer based methodology. These false alarms can cause a lack of confidence in the device by the operator, and eventually the device becomes ineffective.
The instant invention is designed to provide a rollover warning system that addresses the above mentioned problems. The instant invention of a rollover warning system is designed to provide accurate rollover warnings to a driver to prevent or reduce the number of rollovers by vehicles, and is retrofittable, meaning it is not required to be tied into the computer system of a vehicle.